//https://leetcode.cn/problems/find-peak-element/
class Solution {
    public int findPeakElement(int[] nums) {
        int left = 0;
        int right = nums.length-1;
        while (left < right) {
            int mid = left + (right - left) / 2;
            //对于所有有效的 i 都有 nums[i] != nums[i + 1]
            if (nums[mid] < nums[mid+1]) {
                left = mid+1;
            }else {
                right = mid;
            }
        }
        return left;
    }
}